Vapor-electric-arc apparatus



May 8, 1928; 1,669,147

c. A SABBAH VAPOR ELECTRIC ARC APPARATUS Filed July 1926 1 Comme A. Sabbath, b His Aficorney.

Patented May- 8. 19 28.

lJNlTE-DSTATES 1,669,147 PATENT OFFICE.

I OAHILLE SABBAE,', OF SOHENECTADY, NEW YORK, ASSIGNOR TO GENERAL ELEC- TRIO COMPANY, A CORPORATION OF NEW YORK.

VAPOR-ELECTBIC-ARC APPARATUS.

' My invention relates to vapor electric arc apparatus comprising a plurality of anodes, and has for its principal object the provision' of an improved anrangement whereby the are of such apparatus may be readily shiftedfrom one anode to another.

It is customary to provide vapor electr c arc apparatus, such a. a rectifier, with solid anodes made of'a'ny si itable conductive material and withfa vaporizable cathode consisting of a liquid materialsuch as mercury or the like. In the operation of such an apparatus, a comparatively high voltage between the anode and cathode is required to start the arc, only a con'iparatively low voltage betweenthe anode and cathode is required to maintain the are after it has once been started, and current is normally transmitted in one direction between the cathode and anode. Because of the difliculty in starting the are, means are frequently provided for continuously maintaining an exciting arc whereby the apparatus is maid tained in such a'state that the main arc is readily established to the anode having the highest voltage, and is readily shifted from one anode to another-in response to variation in the alternating potentials applied to the anodes. In accordance with-my invention, the necessity of maintaining an exciting arc is avoided by the provision of means operable in response .to decrease in the current of one anode to cause a comparatlvely high starting voltage to be applied to the anode which is the next to transmit the current of the mainlarc. My invention will be better understood from the following description when taken in connection with the accompanying drawing, and its scope will be pointed out in the appended claims.

The drawing shows a. rectifying system wherein my invention has been embodied.

This system comprises direct current terminals 1 and alternating current terminals 2 which are interconnected through a transformer 3 and vapor electric devices 4, 5 and 6. It will be observed that the devices 4, 5 and 6 are provided, respectively, with anodes 7, 8 and 9, and with cathodes 10, 11 and 12; that the direct current terminals 1 v are connected to the neutral of the transformer 3and to the cathodes 10, 11 and 12; and that the secondary terminals of the transformer 3 are connected to the anodes 7; 8 and 9 through the primarycircuits of the current transformers 13, 14 and 15, respectively. A starting battery 16 and switch 17 are provided for initiating operation of the apparatus.

It is known that the current of a mercury rectifier having a transformer of low leakage reactant-e is of substantially rectangular wave form. This means that the current of each anode decreases very rapidly at the end of the positive half cycle. The rapid change in current thus produced at the end of the positive halt cycles is utilized to start the current to the anode which is next to carry the main arc currentof the appara ms. The manner in which this result is accomplished will be readily understood.

Thus, assuming the phase rotation of the transformer 3 to be clockwise and the voltage of anode 9 to be higher than those of anodes T and 8, current will be carried bythe anode 9 until near the end of the positive half cycle of the voltage applied to this anode. Near the end'of this positive half transformer 15 is suddenly decreased and a high voltage induced in the secondary of this transformer is applied between the anode 8 and the'cathode 11, thereby causin the main arc to be established in the device 5 where it is maintained till near the end of cycle, however, the primary current of the-:

the next positive half cycle and from whence it is transferred to the device 4 near. the beginning of the succeeding half cycle, due to the high voltage induced in the secondary circuit of the transformer 14-upon interruption of the current in device 5. The fur? ther operation of the apparatus will be apparent without detailed explanation.

It will be noted that the described method of controlling the apparatus has the advantage that energy is not wasted in maintaining the are, and that the arc is automatically established at the proper instant in each positive half cycle of anode potential.

The embodiment of the invention illustrated and described herein has been selected for the purpose of clearly setting forth the principles involved. It will be apparent, however, that the invention is. susceptible of being modified to meet the different conditions encountered in its use, and I. therefore, aim to cover by the'appended claims all modifications within the true spirit and scope of my invention.

What Itclaim as new, and desire to secure by Letters Patent of the United States, is:

1. The combination of ,polyphase and dione of said polyphase terminals in series with one of said devices and another of which is connected to the cathode and anode of another of said devices.

3. The combination of polyphase and direct current terminals, vapor electric devices each including an anode and a cathode connected between said direct current terminals through a different phase of said ,polyphase terminals, and means including a plurality of'wi'ndings one of which is connected to one of said polyphase terminals in series with one of said devices and another of which is connected to the cathode and anode of another of said devices, said windings being arranged to initiate an arc in one of said devices.

4:. The combination of polyp-base and direct current terminals, vapor electric means including a plurality of anodes each connected to one of said direct current terminals through means including a diflerent one of said polyphase terminals, and means a rrangcd to apply to one of said anodes :1; voltage dependent on the rate of change in the current of another of said anodes whereby current is started through said first-mentioned anode in response to change in the current of said second-mentioned anode.

5. The combination of alternating and direct current terminals, vapor electric means including a plurality of anodes each connected to one of said direct current terminals through means including a difierent one of said alternating current terminals, a transformer provided with a plurality of windings one of which is connected in circuit with one of said anodes and the other of which is conncctedbet-ween another of said anodes and the other of said direct current terminals.

6. The combination of polyphase and direct current terminals, vapor electric means including a plurality of anodes each connected to one of said direct current terminals through means including a different one of said polyphase terminals, transformer means including a primary circuit connected between one of said phase terminals and one of said anodes and a secondary circuit connectedv between another of said anodes and the other of said direct current terminals.

In witnesswhereof, I have hereunto set my hand this 20th day of July, 1926.

CAMILLEA. SABBAH. 

